Plant for hydraulically operating delivery pumps



April 18, 1939. E. T. JDERBLOM PLANT FOR HYDRAULICALLY OPERATING DELIVERY PUMPS Filed Sept. 17, 1957 dal.

Patented Apr. 18, 1939 UNITED STATES `PATENT OFFICE PLANT FOR HYDRAULICALLY OPERATING DELIVERY PUMPS Erik Ture Jderblom, Alnars, Bo, Sweden 2 Claims.

The present invention relates to a plant for hydralically operating delivery pumps, comprising a driving pump set which is connected to the delivery pump through two conduits or pipe lines each of which serves alternately as a driving liquid conduit and as a delivery conduit. A driving pump set according to the invention can be used for driving for instance such deep well pumps as are described in the Swedish Patent No. 88,053. The invention has for its object to provide certain improvements in driving pump sets which serve to regulate the flow of liquid between the driving pump and the delivery pump, which improvements will be more particularly pointed out below.

The invention is illustrated on the accompanying drawing which shows an embodiment of a driving pump set, Figure l showing a vertical View thereof, partly in section, and Figure 2 a detail in plan View.

Referring to the drawing, the driving pump set consists of a piston pump comprising two identically alike coaxially arranged pump cylinders I, 2, each containing a double acting piston 3 or 4 respectively. The two cylinders I, 2 are connected at their outer ends to two conduits A, B which connect the driving liquid spaces of the cylinders with a delivery pump, not shown, and each of which as mentioned above, serves alternately as a driving liquid conduit and a delivery conduit. The two pistons are rigidly connected together by means of a common piston rod 5 which is arranged toI perform a reciprocating movement under the action of a fork-shaped crank rod 6 the arms of which are positioned at opposite sides of the pump cylinder 2 as shown in Figure 2. The piston rod 5, which consists of a tube, is composed according to the drawing of two parts the abutting ends of which are threaded and screwed into a threaded coupling sleeve l. The latter is provided with pivots 8 cooperating with pivot bearings 9 provided at the ends of the arms of the crank rod 6. The described crank rod arrangement has the advantage as compared with a one-sided connection of the crank rod and the piston rod that the piston rod is completely relieved of bending moments in the plane defined by the crank axis and the pivot axis.

The two ends of the tubular piston rod 5 are adapted to be alternately closed by means of valves Il, I2 which are secured at opposite ends of a rod I3 adapted to slide freely in the tube 5. The valves II, I2 and the rod I3 are retained in centered position with respect to the tube 5 by (Cl. 10S- 44) means of guide pins I4. The valves II, I2 are shifted by the liquid pressure in the conduits A and B in such a manner that the valve which is foremost in respect to the direction of movement of the pistons 3, 4 is closed. In Figure 1 the pistons are shown in one end position, viz. in the right hand end position according to the drawing. During the movement of the pistons towards said position as well as in saidend position the valve I 2 is kept closed and the valve il open. The pumped liquid is thus permitted to enter the tube 5 past the open valve Il. The piston rod tube 5 is provided with two ports Il, I8 controlled by non-return Valves I5, I6 or the like through which ports the pumped liquid in the tube 5 can pass to the parts of the cylinders I and 2 positioned between the pistons 3 and 4 which parts constitute the actual delivery cylinder spaces. Said cylinder spaces communicate through channels 2l and 22, pipes 23 and 24, and a common pipe socket with a collecting tank 26 for the delivered liquid. The outlets of the channels 2l and 22 are controlled by non-return valves 2l so that pumped liquid from the cylinders can pass into the pipes 23 and 24 but not the other way. Said tank preferably consists of a so called storage tank of known construction, in which the liquid is subjected to the pressure of an entrapped volume of air and the level of liquid is controlled by level regulating members, not shown. The remote ends of the cylinders I and I 2 are connected by means of pipes 28 with a spare liquid container or iioat housing 29 which is in direct communication with the external airv and the oat 3G of which controls in known manner by means of a valve 3| an inlet opening constituting the mouth of a pipe 32 the other end of which is connected to the pipe socket 25 so that on opening of the valve 3l liquid is supplied to the float housing 29 from the tank 26. The pipes 28 are connected to depending pipe sockets 33 and 35i respectively opening near the bottom of the float housing 29 and containing non-return valves 35 and 35 respectively. Said valves are so ar- 45 ranged as to permit supply of liquid only in the direction from the housing 29 to the cylinders.

The pump is preferably driven by a motor. According to the embodiment shown, designates an electric motor which drives a gearing 4I, 42 by means of a belt, the crank rod 6 being connected with a crank pin 43 arranged on the gear wheel 42. The motor 40 can be started and stopped in known manner through the intermedium of electric switching members in dependence of the position of the level regulating member provided in the storage tank.

The two pump cylinders I, 2, the float housing 29, the tank 26 and the appertaining pipe lines and the driving mechanism can advantageously be assembled so as to form a single unit as indicated on the drawing. On the drawing a plate 50 forms a foundation provided with uprights 5I and 52 which support the cylinders I and 2 and the motor 4D. The tank 26, together with bearing housings for the gearings 4I, 42, if provided, can be placed directly on the foundation plate. The uprights 5I for the cylinders I and 2 are mutually braced by means of a wall or web 53 extending along the cylinders.

The described arrangement operates in the following manner.

On displacement of the pistons 3 and 4 towards the end position shown on the drawing there is initially produced a driving pressure in the conduit A which causes the delivery pump not shown to start its operation. Due to the operation of the delivery pump a certain amount of liquid is forced through conduit B which liquid normally, as the piston 3 moves to the right, fills the fore space of the cylinder I and in addition iiows past the valve II, which is open during said movement of the piston, through the tubular piston rod 5 and into the part of the space of the cylinder 2 which is behind the piston 4, the liquid then passing through the port I8 in the piston rod wall controlled by the non-return valve I6. During the following piston movement in the opposite direction, when the valve II is closed and a driving pressure is produced in the conduit B, the piston 4 presses the liquid which has entered the cylinder 2 through the port I 8 and the feed conduit 24 into the collecting tank 26. At the same time delivered liquid passes into the cylinder I past the valve I2, which is now open, and through the port I'I filling said part of the cylinder,

In case the rating of the delivery pump and other working conditions are such that the amount of liquid delivered is equal to the cylinder volume on the suction side of the pistons, which can be considered as the normal condition, the delivery is effected in the above described manner. If, on the other hand, the delivered amount of liquid is greater, the surplus amount is pressed into the tank 26 already during the delivery stroke through the valve ports II, I8 and the feed pipes 23, 24, whereafter the remaining normal amount of liquid is forced into the tank 26 in the above described manner during the following stroke of the piston.

If instead on account of an abnormal operation of the delivery pump or due to lack of liquid the delivered amount of liquid momentarily should be smaller than the normal one there is created in the described embodiment a subpressure behind the piston producing the driving pressure, but the proper functioning of the driving set is in no Way disturbed thereby since the conduits A and B are always kept filled with liquid through the intermedium of the spare liquid container .29.

During periods of rest leakage losses in the delivery pump and in the conduits A and B are covered by said container 29 as long as it is supplied with liquid from the collecting tank.

I claim:

1. In a hydraulic system for driving deep well pumps the combination of two pump cylinders arranged substantially in line, a double-acting piston in each of said cylinders, a hollow pistonrod connecting and substantially traversing said pistons so as to form a connecting conduit between the spaces of said cylinders on turnedaway sides of said pistons, a valve at each end of said piston-rod, a rod slidably arranged within said piston-rod and connecting said valves so as to cause the opening of one valve if the other is closed and vice versa, a port each in the wall of said piston-rod where it extends into each of said cylinders, a non-return valve in each of said ports adapted to release liquid into the space of said cylinder, supply conduits connected to the turned-away sides of said cylinders, outlets at the sides of said cylinders facing each other, and power-driven means for reciprocating said pistons within said cylinders.

2. In a hydraulic system as described in claim 1, non-return valves in said outlets adapted to release liquid from said cylinder-sides, a storage tank, conduits connecting said outlets through said non-return valves with said tank, a spare liquid container, conduits connecting said container with the turned-away sides of said cylinders, and non-return valves associated with said last mentioned conduits adapted to release liquid from said container through said conduits to said 

